Telephone-exchange system



C. L. GOODRUM.

TELEPHONE EXCHANGE SYSIEM. APPLICATION FILED 0cT. 25. 1918.

1,393,522, Patented Oct. 11,1921."

/m/enfor': Char/a5 A. boar'um.

. UNITED, STATES PATENT ()FFl-CE.

CHARLES I. GOODR'UIMI, OF NEW'YORK, N. Y., ASSIGNOR T0 WESTERN ELECTRIC COM- .IANY, INCORPORATED, OF NEW YORK, N. Y'., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHAN GE SYSTEM.

Specification of Letters Patent. Patented Oct, 11, 1921,

Application filed October 25, 1918. Serial No. 259,629;

To all whom it may concern 7 Be it known that I, CHARLES L. GooDRUM, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Telephonexchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to improvements in automatic telephone exchange systems and has particular reference to circuit arrangements for selector switches employed therein.

Heretofore, in two-wire automatic telephone exchange systems it has-been customary to include one or more slow-to-release relays for controlling the primary and secondary steppingcircuits of a selector switch. Such slow relays have their circuits interrupted by impulses sent over the telephone line but, due to their structure, the same are not suiiiciently denergized to permit their armatures to retract until a prolonged interruption occurs, whereupon certain changes are eifected to complete the operation of the switch.

I An object of this invention is to improve the construction and operation of selector switches by dispensing with the slow-to-re lease relays and providing contacts for the impulse receiving device of the selector switch, such as a line relay, one of said contacts being actuated in response to each operation of an impulse device at the calling subscribers substation, and another contact being actuated in response to certain operations only of said impulse receiving device.

Another object is to release the selectively operable switch by a contact actuated, upon the permanent restoration of the impulse receiving device,,to operate another contact which controls the release circuit of said switch, the second named contact being normally out of operative relation with said impulse receiving device and moved into operative relation therewith upon the initial energization of said device.

Briefly stated, the invention includes a slow moving or a sluggish device which is preferably associated with an impulse receiving device, such as a line relay, and provided with front and back contacts normally out of engagementwith the armature of said relay but ,arrang'edrso that when the a s initially energized the" device w n he moved to a position where the armature, upon being vibrated in response to the line 1nterruptions, will engage the back contact and close, the primary stepping circuit of the selector switch. The device vbeing sluggish in operation remains in its initiallymoved position during the vibrations of the armature.- At the termination of the line interruptions the usual escape magnet is energized to move the side switch of the selector into trunk hunting position, after which the magnet of the secondary stepping circuit will be energized to again step the selector in the usual manner to find an idle trunk. Upon the permanent restoration of the line relay by the'replacing of the calling subscribers receiver upon. its switchhook during a period of-time before the completion of the operation of the selector switch or at the termination of the conversation, the slow-acting contact-carrying device is returned to normal and closes a releasing circuit which aids in disconnecting the calling and called lines.

The inventive idea involved is capable of receiving a variety of expressions, one of which, for the purpose of illustrating the invention, is shown in the accompanying drawing; but it is to be expressly understood that said drawing is utilized only for the purpose of facilitating the description of the invention as a whole and not todefine the limits thereof, reference being had to the appended claims for this purpose' The drawing illustrates diagrammatically a telephone exchange system, only so much being shown of the circuit arrangements and apparatus as is necessary for a complete understanding of this invention.

The mechanical construction and operation of the selector switches and other apparatus used in establishing a connection between a calling and a calledline, are features well known in the art, and therefore, in the following a detailed description will be given only of the operation of a selector switch used in the establishment of a connection.

The subscriber at substation 1, desiring a connection with substation 2, removes his receiver from its switchhook and causes the operation, in a well-known manner, of cer-' tain apparatus, such ,I as a trunk finder or a lineswitch (not shown) to select an idle When an'idle trunk is found, a circuit closed from grounded battery 4, left-hand winding of, line relay 5, wiper 6 of the side switch associated with. the ;switch 3, substation apparatus 1, wiper 7 of said side switch and right-hand windingio'f lin'e 're-, lay to ground. The slow-acting or sluggish device '8 is pi-votallyv mounted-at 9 and carries contacts 10 and 11 arranged to be engaged by the armature 12. The armature 12 of the line relay isnormally positioned between and out of engagement with the contacts 10 and 11. Upon the energization of line relay '5, armature 12 will pull up ruption of said circuit, armature 12 en gages contact 11 and closes a circuit for primary stepping magnet 13 extending i'rom grounded battery 14 through the winding' o'fjsaid magnet, wiper'15 of the side switch'in its firs'taposition, contact 11 and armature 12, t'o'groundl 'The primary magnet 13 will step theselector switch in a man- 'ner well known in the art, until the first series of impulses sent from the calling device is completed, whereuponfarmature 12 will be held attracted by linerelay '5 for closing the operating circuitoi slow-acting escape mag'net 16, "which circuit extends from grounded battery 14, winding of escape magnet 16, off-normal contact 17, which is closed upon the first stepof the'selector switch, side-switch wiper 18 in itsfirst position, resistance 19, contact '10 and'ar'ma- 't'ure 12, to ground; 'Esoape-'magnet 16 is consequently energized, due to the prolonged engagement oi" armature .12 with front con-' tact 10, and moves the side switch into second position, whereupon the :circuit for the primary magnet 13 is broken and another circuit for the secondary stepping magnet 20 closed which extendsi'rom grounded battery 14, winding of secondary magnet 20, armature and back contact thereof, wiper 21 of the "side switch, ito ground." v The secondary magnet'20'is operated tocontrol the secondary stepping circuit of the selector switch 3; As'long as the test brush 22 of the selector switch travels over terminals of busy trunks, no ground will be found for escape magnet 16, the'circuit'for which now extends fromgrounded contact 14, winding of, magnet 16, ofii-normal contact 17 wiper '18 in' its second position and test brush 22.

.As soon as said brush-reaches the terminal of idle trunk, that is, one to which ground is oconnected, the cir'cuit 'for' said of the side switch are caused move into i 2 position 3, in which position the calling line-is extended through the rwipersv'6- and}? mechanism (not shown) provided between the selector 1-3 :and the called substation 2,

and under the control of substation 1 the desired connection may be established inthe well-known manner.

"Upon the severing of the connection, a

ground is sent from the above-mentioned pf the side switch to, another switching" switching mechanism through brush '22,"

wiper 26, conductor 25 g and winding of re lease'magnet 24, tofgrounded battery 14, whereupon said release-magnet :Wlllbfl energiz ed in'a well-known rnan lei and return ,thefseljector switch 8 and associated side switchito normal'position. Aiter thefside swit'ch'has been restored to normal and'tlie receiver at substation 1 replaced, line,relay 5 deenergized, and armature 12'momentarily engages contact 11 and returns the device 8 to normal p'osition, I whereupon a ground is y, sent from spring contact "23 through 'condu'ctors' 28 and 29 {and wiper 30 to the trunk fi fil ri l 'switclhi Pil viously referr'ed' to but not shown, or causing the release thereofi] p g H Should the subscriber at substation L1 fabandon his call before'the completion of the operationofthe primary and secondary stepping circuits, line relay-5 will be defenerg'ize'd and the device 'l8 m'ov ed to'its nor mal position. In this position the spring contact23willibe closed, saidcontact' having moved to open position upon the fir'st energization. of line relay 5, and :a circuit for release inagne't 24.1lwill be closed which,

extends from grounded vbattery 14, winding of release magnetl-24,'conductor 25', side? switch wiper'26 in either its first orjsecond positions,- off normal contact 27, conductor energization '01 release magn'et 24 will return the selector switch to normal position in the well-known manner. I F f "What is claimed is: i v g f1. Ina telephone exchange'system including incoming and outgoing lines, a selector series of impulses from said senderuto cause the operation of said secondary magnet, and a :third Contact for said line; relay in the ii i of Tss i islets ima e-e we: li ies-s 28 and springconta'c't 23, to. ground. "The i magnetactuated upon the'termination'of a control of said line relay but actuated only in response to certain operations thereof.

2. In a telephone exchange system including incoming and outgoing lines, a selector switch for extending an incoming line toward an outgoing line, a line relay associated with said selector switch, primary and secondary means for controlling the operation of said switch, a single movable means arranged in operative relation to said line relay for controlling the operation of said primary and secondary means, and means also controlled by said movable means for releasing said selector switch.

3. In a telephone exchange system including incoming and outgoing lines, a selector switch for extending an incoming line toward an outgoing line, a line relay associated with said selector switch, primary and secondary means for controlling the operation of said switch and a contact-carrying device associated with the armature of said line relay for controlling said primary and secondary means, the contacts of said device being normally out of engagement with said armature and moved into cooperative relation therewith upon energization of said relay.

4:. In a telephone exchange system including incoming and outgoing lines, a selector switch for extending an incoming line toward an outgoing line, a line relay associated with said selector switch, primary and secondary means for controlling the operation of said switch, and a rotatable device associated with the armature of said.

line relay and actuated in one direction thereby to cooperate therewith in controlling said primary and secondary means.

5. In a telephone exchange system includ ing incoming and outgoing lines, a selector switch for extending an incoming line toward an outgoing line, a line relay associated with said selector switch, primary and secondary means for controlling the operation of said switch, a release circuit for said switch, and a rotatable device associated with the armature of said line relay and actuated in one direction thereby to cooperate therewith in controlling said primary and secondary means, said device being movable in an opposite direction upon'deenergization of said line relay to close said release circuit.

6. In a telephone exchange system including calling and called subscribers lines, a selector switch for extending a calling subscribers line toward a called, subscribers line, a line relay associated with said selector switch, means for operating said switch, a release circuit for the said switch, a movable contact-carrying device in operative relation to said line relay and actuated thereby to control the operating means of said switch, and means controlled by said device for closing said release circuit should a calling subscriber replace his receiver during the operation of said operating means.

7. In a telephone exchange system, an incoming line, a switch for extending said line, primar and secondary stepping magnets for operating said switch, an escape magnet for controlling the operation of said secondary stepping magnet, and a relay connected to said incoming line, said relay having contacts in the circuits of said primary and escape magnets, the contact in the circuit of said escape magnet being closed upon energization of said relay.

8. In a telephone exchange system, an incoming line, a switch for extending said line, a stepping magnet and an escape magnet for said switch, a relay connected directly to said incoming line, and circuits for said stepping and escape magnets passing through contacts of said relay, the contact in circuit with said escape magnet being closed upon energization of said relay.

9. In a telephone exchange system, an incoming line, a switch for extending said line, a stepping magnet, an escape magnet and a release magnet for said switch, a re lay operable over said incoming line, and circuits for said magnets passing through contacts of said relay, the contact through which the circuit of said release magnet passes remaining open during the operation of said switch.

In witness whereof I hereunto subscribe my name this 21st day of October, A. D. 1918.

CHARLES L. GOODRUM. 

